Fabrication of self-aligned silicon field emitters coated with diamond-like carbon

A silicon emitter array was fabricated on an n-type wafer using conventional dry etch and sharpening oxidation method. The diamond-like carbon (DLC) film was deposited onto the silicon tips using radio frequency plasma-assisted chemical vapor deposition. The silicon tips were cleaned either by dipping in buffered hydrofluoric acid (HF) for a minute or argon ion bombarding in the deposition chamber. HF cleaning did not result in uniform DLC coating, while argon bombarding increased the aspect ratio of the tips due to the angle dependence etching. Furthermore, DLC films adhere better on the argon bombardment tips than on the HF-treated silicon tips producing samples which emitted current at the onset voltage as low as 20 V.